Identification of selected moulds and yeasts
A total of 119 strains, comprising 53 moulds, 51 yeasts
and 15 bacteria, was isolated. This investigation focussed
on improving performance, so the isolated fungi were
subjected to a screening program of which the main
outcomes are summarized in Table 3. Three main groups of
moulds and yeasts were distinguished according to their
starch degradation and ethanol production, respectively.
Eight mould isolates expressing strong starch degrading
ability that was evaluated by measuring diameters of
clearing zones in rice-starch agar, were selected for further
studies and identified as four species, namely Amylomyces
rouxii, Amylomyces aff. rouxii (an atypical form of A.
rouxii), Rhizopus oligosporus and Rhizopus oryzae. These
species were also found earlier in amylolytic fermentation
starters used in the production of alcoholic beverages in
various Asian countries (Hesseltine et al., 1988; Nout &
Aidoo, 2002). All species belong to genera of the
Zygomycetes, which are commonly found in foods; these
are confined to the order Mucorales